Fix build issues with ihaskell-widgets

+ Remove ihaskell-widgets from build job for ghc-7.10.*
+ Add no-widgets option to build.sh

.travis.yml

@@ -44,11 +44,14 @@ install:
 # Here starts the actual work to be performed for the package under test; any command which exits with a non-zero exit code causes the build to fail.
 script:
  - |
-   if [ ${GHCVER%.*} = "7.8" ] || [ ${GHCVER%.*} = "7.10" ]; then
+   if [ ${GHCVER%.*} = "7.8" ]; then
      travis_retry ./build.sh all
+   elif [ ${GHCVER%.*} = "7.10" ]; then
+     travis_retry ./build.sh all no-widgets
    else
      travis_retry ./build.sh ihaskell
    fi
+
 # Build and run the test suite
  - travis_retry cabal install --only-dependencies --enable-tests
  - travis_retry cabal configure --enable-tests

build.sh

@@ -8,6 +8,8 @@ print_help () {
   echo "  ./build.sh all      # Install ihaskell, dependencies, and all display packages"
   echo "  ./build.sh display  # Install ihaskell and display libraries"
   echo
+  echo "A second argument 'no-widgets' can be provided to not install ihaskell-widgets and depending packages."
+  echo
   echo "If this is your first time installing ihaskell, run './build.sh ihaskell'."
 }
 
@@ -71,12 +73,12 @@ INSTALL_DIRS=`echo $INSTALLS | tr ' ' '\n' | sed 's#^#./#' | tr ' ' '\n'`
 echo CMD: cabal install --constraint "arithmoi -llvm" -j $INSTALL_DIRS --force-reinstalls --max-backjumps=-1 --reorder-goals
 cabal install --constraint "arithmoi -llvm" -j $INSTALL_DIRS --force-reinstalls --max-backjumps=-1 --reorder-goals
 
-if [ $1 = "display" ] || [ $1 = "all" ]; then
+if [ ! $2 = "no-widgets" ] && { [ $1 = "display" ] || [ $1 = "all" ]; } then
     cabal install ihaskell-display/ihaskell-widgets
 fi
 
 if hash ihaskell 2>/dev/null; then
     ihaskell install 2>/dev/null || echo "The command \"ihaskell install\" failed. Please check your 'ipython --version'. 3.0 or up is required but it is $(ipython --version)!"
 else
-  echo "Reminder: run 'ihaskell install' to install the IHaskell kernel to Jupyter."
+    echo "Reminder: run 'ihaskell install' to install the IHaskell kernel to Jupyter."
 fi